This map shows how easily something very bad could happen over Syria

Russia started bombing targets in Syria last week, avoiding the strongholds of ISIS — the terror group they claim to be bombing — and instead going after CIA-backed rebels and others who are fighting the regime of Syrian President Bashar Assad, who the US has said must step aside if ISIS is to be defeated.

Recently during their bombing campaign, Russian jets “had their closest run-in yet” with American planes, according to CBS. They were reportedly within 20 miles of each other, close enough that Americans could see the Russian planes on their targeting cameras.

The green planes are American aircraft and the yellow planes are Russian:

Lt. Gen. Charles Brown, commander of the American air campaign in Syria, told CBS that the US has just been working around the Russians as they have entered Syrian airspace to conduct strikes against anti-regime rebels and extremist factions.

“We’re up a lot more often than [the Russians] are so when we do have to move around [them] for safe operation, it’s for a small period of time compared to the hours and hours that we’re airborne over Iraq and Syria,” Brown said.

Brown said he doesn’t think Russian airstrikes will clash with American operations, but some experts have said that there are significant risks associated with the US-led anti-ISIS coalition occupying the same airspace as Russia.

“While the US and Russia will engage in direct military talks to ‘deconflict’ any strikes, the chances for accidents go way up — especially given the many military members of the coalition,” geopolitical expert Ian Bremmer, president of the Eurasia Group, told Business Insider last week.

“The US and allies will ignore Russian calls to avoid Syrian airspace the same way the Russians ignored the US on Assad.”

Russia gave the US little notice before it started bombing rebel groups fighting the regime of Assad, a close ally of Russia.

The Associated Press noted this week that “the air forces of multiple countries are on the attack, often at cross purposes in Syria’s civil war, sometimes without coordination,” emphasising the potential for “unintended conflict.”

Turkey, Australia, France, and the US are all flying planes over Syria, and Russia is not coordinating with the Americans, according to the AP. Defence officials from the US and Russia have had conversations about “de-conflicting” their activities in Syria, and those discussions are ongoing.